Excited by the cardiac pacemaking and conduction system

The heart beats 2 to 3 billion times during the lifespan of the average person. Each of these muscular cycles of contraction depends on specialized cardiac tissues involved in the rhythmic generation and coordinated spread of electrical excitation. Collectively, these essential tissues are known as the cardiac pacemaking and conduction system. Since these tissues are vital for generating and synchronizing the heartbeat, their dysfunction can be a direct cause of conduction disturbance, arrhythmia and sudden cardiac death. Beginning with Tawara, Einthoven and other pioneering workers, a wealth of information has been collected this past century on the histologic, morphologic and physiologic characteristics of specialized cardiac tissues. More recently, fueled by advances in modern biology, the cellular and molecular mechanisms governing development and function of pacemaking and conduction tissues are now starting to be understood. Questions being actively addressed include: How do the sinuatrial and atrioventricular nodes work? How is development of the His-Purkinje system orchestrated? Can bio-pacemakers be developed as an alternate to electronic pacemakers? The contents of this special issue of the Anatomical Record on “The Cardiac Pacemaking and Conduction System” address such questions, as well as some of the other most interesting issues and advances in the field. The articles are based upon presentations given to a two-day symposium on “The Cardiac Pacemaking and Conduction System” at the FASEB Experimental Biology meeting in Washington D.C. in April 2004. The meeting was sponsored, organized and funded by the American Association of Anatomists. The National Heart Lung and Blood Institute of the NIH and the March of Dimes Birth Defects Association provided grants to support this symposium. Also acknowledged is the generosity of the Japanese Anatomical Association who funded the participation of two of their members at the symposium - Drs Shimada and Nishii. We would like to express our personal gratitude to Andrea Pendleton, Jackie Watling and other AAA staff for their tireless efforts and also to Dr Roger Markwald the Editor of the Anatomical Record who provided funds from journal coffers in support of the meeting and also agreed to publish its proceedings in this special issue. A final note of thanks to all those colleagues who assisted with reviewing the articles contained herein. The proceedings of the meeting and other links of interest to the field can be found at: http://cba.musc.edu/cdbc/conduction. This is an exciting time for those working on the cardiac pacemaking and conduction system. We would hope that the 2004 Washington symposia will be one link in a successful chain of ongoing gatherings of those interested in advancing this important and fast-moving area of biomedicine.

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